Gene Expression in Giardia lamblia

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Every cell within a multicellular organism, such as a human, contains the same genetic blueprint - so what makes a blood cell different from a muscle cell? The answer is how the genetic material is activated. Different cell types activate different sets of genes to make proteins that are specific for the function of the particular cell. For example, a blood cell would produce a protein for carrying oxygen through the body, while a muscle cell would produce a protein that is used for cell contraction. The process of this differential gene activation is referred to as gene expression. The long term goal of our research is to study the regulation of gene expression in the protist, Giardia lamblia (syn. G. intestinalis). Giardia is a common contaminant of freshwaters worldwide including all regions in Canada, and its ingestion by humans causes an infectious form of diarrhea. Giardia is a eukaryote, like a human cell, because its genes are located in a special compartment within the cell called the nucleus. However, the components (i.e. proteins) required to regulate gene expression and other biological pathways in Giardia are greatly reduced and less complex than those in a human. Therefore, the study of Giardia would be an opportunity to identify the bare essentials of these processes in a streamlined biological system. Moreover, these studies may identify unique aspects of these pathways in Giardia that can be exploited to develop improved and more effective treatments of Giardia infections. Our short-term aims for this granting period are: 1) To study gene expression and regulation of the Giardia cell cycle - a process where the cell grows and divides to produce two daughter cells. 2) To characterize the role of a Giardia protein (TBP) in transcription regulation - the process when RNA is produced from its corresponding gene. 3) To examine the role of three related heme proteins in the regulation of gene expression and the transition of Giardia into its infectious form. This NSERC grant would provide support to an exciting and fundamental research program to understand how a parasite commonly found in Canada determines which part of its genetic material gets activated to make a functional product. The funding would also support the training of graduate and undergraduate students in leading edge techniques in molecular biology, microbiology and biochemistry.